1. Field of the Invention
This invention relates to devices for converting ocean wave action to electrical current as a useful energy source. More specifically, the invention pertains to underwater devices which are positioned at the ocean floor and respond to changes in wave height to supply variable pressures or water movement at the transducer.
2. Related Art
The abundance of energy contained in ocean waves has long been recognized. It has been estimated that over 20,000 km of coastline throughout the world may be suitable for harnessing wave power for conversion to electrical power by means of some type of power transducer. In systems close to the shore, the estimated average energy available is approximately 40 to 70 kW per meter of shoreline in energy rich coastal areas, and approximately 10 to 20 kW/m in areas of lesser wave activity. This extensive power resource has been acknowledged by a number of countries, as well as several private industries. Several large power installations have been constructed in an effort to capitalize on this renewable energy source.
Despite much effort and some recent progress, extracting this energy in a practical, cost effective system remains a formidable challenge. The difficulty of energy conversion within the ocean environment arises from the rather hostile conditions that must be overcome. For example, the saltwater conditions are chemically aggressive and contain marine life that result in biofouling of the operating system, further adding to the dynamic state of unpredictable change. In addition to salt water, sand and marine life, weather conditions can generate extreme conditions, particularly at ocean surfaces and shoreline. Storm activity and winds have destroyed countless devices that have endeavored to extract energy from wave movements at the ocean surface, requiring high costs of maintenance and replacement that have labeled wave energy technology as generally uneconomical.
U.S. Pat. No. 6,700,217 leading to the present invention disclosed a variety of devices that are positioned on the ocean floor, preferably at depths between 5 and 30 meters, significantly reducing exposure to adverse weather and wind conditions. As waves move above the device, the water level changes, causing a pressure differential to be variably applied to the transducer. These pressure changes register at the transducer and are converted by electro-mechanical devices into electricity. Several of the disclosed devices include coil/magnet combinations as the operative component for changing mechanical movement into electrical current. This current is transmitted to a shore location for storage in a battery pack or other location for use.